The poll will make depressing reading for Alex Salmond, who will feel frustrated that he is getting such little traction on a central issue to voters.

However, there is still room for manoeuvre ahead of the referendum later this year.

While only nine per cent said independence would make them better off, a minority of just 29% believed they would be worse off.

Thirty per cent of people thought independence would be good for the Scottish economy and 34% believed it would be bad.

"Voters want to hear about the economic and financial consequences of the choice that they make, and it is on the outcome of that debate that the result of the referendum is likely to turn," professor John Curtice, research consultant at ScotCen Social Research, said.

"The referendum campaign is at risk of short-changing the people of Scotland. So far it appears to have done little to help them be clear and confident about the decision they have to make.

"Many of the issues that preoccupy those campaigning for and against independence are apparently of peripheral interest to voters."

The polling found issues central to the independence debate such as EU membership, currency and welfare made little difference to voters' intentions.

The way the campaign has been fought also appears to have done little to inform the public.

Just 22% said they felt they knew 'a great deal' or 'quite a lot' about independence, while 37% said they did not know very much or anything at all.

But the nationalists still have a struggle on their hands if they intend to turn the tables in the referendum with only small changes in levels of support taking place last year.

Support for independence currently stands at 29% - up six points since 2012 but still down three from 2011.

The poll suggests Westminster won a major coup when it prevented Salmond putting a third 'devo-max' option on the referendum paper.

The 38% of Scottish voters unsure how they will vote are particularly sympathetic to bolstering the Scottish parliament's powers.

Forty-two per cent of them want the Scottish parliament to make all decisions for Scotland outside of defence and foreign affairs – ten points higher than among Scots as a whole.

Sixty per cent of waverers said they wanted more than just a 'yes' and 'no' option, compared to 52% of all Scots.